The invention relates generally to drive mechanisms, and more specifically to a drive mechanism particularly suitable for ambulators in providing a low center of gravity and a high degree of maneuverability.
Numerous types of general purpose and specific purpose wheelchairs have been designed in an effort to accommodate the various needs of the orthopedically disabled. One specific need for a paraplegically disabled person is to be supported in a standing position to accomplish such tasks as may be required in such a position.
One such development is represented by U.S. Pat. No. 4,054,319 issued on Oct. 18, 1977 for a "Stand-Aid Invalid Wheelchair". This patented device provides a wheelchair to support a paraplegic in both a standing and seated position, and having linkage for moving the paraplegic to and from both positions. Although such a wheelchair represents an important advance in the art, because of its size it cannot operate in confined spaces, nor is it highly maneuverable, i.e. capable of spinning around a vertical axis. In a copending U.S. patent application, Ser. No. 062,835, and further identified as Navy Case No. 62,921, a wheelchair and stand up ambulator are constructed as separable units, with the ambulator detachable in order for the occupant to accomplish certain tasks while in a standing position apart from the wheelchair. The present invention is directed to the specific drive mechanism for the ambulator unit. The specific linkage which supports the occupant in a standing position on the ambulator is also covered in copending U.S. patent application, Ser. No. 062,835.